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In wireless communication systems, signal space diversity techniques are usually adopted to combat channel fading by exploiting time diversity, frequency diversity, spatial diversity or a combination of them. Most existing schemes to achieve signal space diversity are based on linear constellation spreading. In this paper, we propose a novel nonlinear signal space diversity technique based on maximum...
We examine various algebraic/combinatorial properties of Low-Density Parity-Check codes as predictors for the performance of the sum-product algorithm on the AWGN channel in the error floor region. We consider three families of check matrices, two algebraically constructed and one sampled from an ensemble, expurgated to remove short cycles. The three families have similar properties, all are (3; 6)-regular,...
This study discussed the decoding mechanism of block product turbo code (BPTC) (196,96) and analyzed its efficiency, used the Hamming (15,11) and Hamming (13,9) block channel code combinations and block interleaving to construct a BPSK modulation and BPTC (196,96) coding system in the concept of feedback encoding in turbo code. The system is based on the Analog Device DSP platform, the C code is used...
In this paper a new scheme is proposed for progressive image transmission over coded Orthogonal Frequency Division Multiplexing (OFDM) system with Low Density Parity Check Coding (LDPC). Trigonometric transforms are used in this scheme for improving the performance of the OFDM systems and reducing the Peak-to-Average Power Ratio (PAPR) of OFDM signal. It improves the error resilience ability and transmission...
High rate low-density parity-check (LDPC) codes have been under intense research in the serial concatenation of inner Extend partial-response Class 4(EPR4) and outer LDPC codes due to their decoding performance close to the Shannon capacity. The Accumulate Repeat-3 and Accumulate (AR3A) codes, viewed as a subclass of protograph LDPC codes, achieve good decoding performance with simple linear encoder...
Firstly, this paper gives a simple introduction of the encoding/decoding theory of LDPC and Space-time coding. And it carries out a detailed research and analysis on LDPC coding system and the space-time block coding system. Then, LDPC and space-time coding are combined. The performance of LDPC-STBC under AWGN channel is given through computer simulation. The simulation results show that this method...
Streaming degradable content (such as video or audio) over a wireless channel presents new challenges to modern digital design, which was founded on the separation theorem of Shannon theory. Joint source-channel coding (JSCC) has recently received increasing interest to address the varying nature of the wireless channel conditions (under mobility or multicast). The conventional approach to JSCC which...
Turbo codes play an important role in making communications systems more efficient and reliable. This paper provides a description of two turbo codes algorithms. Soft-output Viterbi algorithm and logarithmic-maximum a posteriori turbo decoding algorithms are the two candidates for decoding turbo codes. Soft-input soft-output (SISO) turbo decoder based on soft-output Viterbi algorithm (SOVA) and the...
We consider serial concatenation of a Luby Transform (LT) code with a differential quadrature phase-shift-keying (DQPSK) modulator for transmission over an additive white Gaussian noise (AWGN) Channel. Assuming a target average rate for the operation of the rateless LT DQPSK scheme, the degree distribution of the LT code is optimized in terms of convergence threshold using extrinsic information transfer...
In this paper, the performance evaluation of an asymmetric turbo code for different codec parameters have been done. The asymmetric turbo codes performances are compared with symmetric counter part of the turbo code. With proper selection of weight configuration, the turbo code can show better results in both water fall region as well as error floor region simultaneously. So, in some cases asymmetric...
In this paper we prove the separation of source-network coding and channel coding in a wireline network, which is a network of memoryless point-to-point finite-alphabet channels used to transmit correlated sources. In deriving this result, we also prove that in a general memoryless network with correlated sources lossless and zero-distortion reconstruction are equivalent provided that the conditional...
Theoretical analysis has long indicated that feedback improves the error exponent but not the capacity of memoryless Gaussian channels. Chen et al. demonstrated that a modified incremental redundancy scheme can use noiseless feedback to help short convolutional codes deliver the bit-error-rate performance of a long blocklength turbo code, but with much lower latency. This paper presents a code-independent...
It has previously been shown that ensembles of terminated protograph-based low-density parity-check (LDPC) convolutional codes have a typical minimum distance that grows linearly with block length and that they are capable of achieving capacity approaching iterative decoding thresholds on the binary erasure channel (BEC). In this paper, we review a recent result that the dramatic threshold improvement...
In this paper, we discuss the combination of non-binary channel coding with higher-order modulation and MIMO transmission in the form of spatial multiplexing. In addition to the benefits of non-binary LDPC codes on the AWGN channel, we identify an inherent advantage for non-binary coding in multiple antenna schemes. By comparing binary and q-ary information processing at the receiver, we highlight...
Distributed coding has been shown to be an efficient scheme to improve the performance of wireless relay networks. In this paper we propose an analog distributed channel coding (ADC) scheme. In the proposed scheme, the intermediate relays directly process the received analog noisy signals without making the hard estimation and performs analog channel encoding of the noisy soft estimates of the transmitted...
Increasing the symbol rate up to 25% faster than the Nyquist criteria for a digital communications system with QPSK modulation with an AWGN channel does not significantly increase the bit error rate or required transmission bandwidth. This so-called Faster-than-Nyquist (FTN) signalling has not been used in commercially deployed communications systems since the previously proposed implementation schemes...
Signal space diversity technique has been widely adopted in wireless communication systems to combat channel fading by exploiting time diversity, frequency diversity, spatial diversity or a combination of them. Most existing signal space diversity schemes are based on linear constellation spreading. In this paper, we propose a novel nonlinear signal space diversity technique based on maximum distance...
This article has researched encoding and decoding algorithms of Turbo Product Codes focusing on analysis of Chase-Pyndiah algorithm-based soft in/soft out (SISO) iterative decoding algorithm. The algorithm simulation done under matlab7.0 environment shows that, on an AWGN channel using BPSK modulation, Turbo Product Codes do a similar decoding performance as Turbo codes with a simpler decoding method...
In coding theory, concatenated codes form a class of error-correcting codes that are derived by combining an inner code with an outer code. This is a solution to the problem of finding a code that has both exponentially decreasing error probability with increasing block length and polynomial-time decoding complexity. The work presented in this paper, provides link level performance analysis of non-line...
The communication problem over the N-sender additive white Gaussian noise (AWGN) multiple access channel (MAC) with feedback is considered. It is shown that Kramer's code, which is known to be sum rate optimal in the class of generalized linear feedback codes, can be obtained by solving a linear quadratic Gaussian (LQG) control problem. This generalizes the previous result of Elia, which recovers...
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